This invention relates to homopolymers of arylcyclobutene functional monomers and copolymers of arylcyclobutene functional monomers with vinylaromatic monomers having a high degree of syndiotacticity. This invention also relates to a process for preparing such polymers and a polymeric composition comprising such polymers. The introduction of arylcyclobutene groups into these polymers allows such polymers to undergo ring opening, crosslinking and grafting reactions when heated. The resulting products have improved physical properties such as char formation, softening point, and solvent and wear resistance. The polymers of the present invention may be employed as synthetic polymers in typical plastics operations such as in producing extruded and molded parts.
In U.S. Pat. No. 4,540,763, poly(arylcyclobutene) polymers are disclosed. The polymers are prepared by subjecting poly(arylcyclobutene) compounds to ring-opening conditions such as heat and linking the compounds together through such opened rings. The polymers so formed exhibit excellent physical properties, such as high thermal stability, low dielectric constant, and low moisture and solvent absorption. Because of such properties, the polymers are useful in preparing composites, and in several electronics applications.
U.S. Pat. No. 4,667,004 discloses solid homopolymers of an olefinic benzocyclobutene monomer. U.S. Pat. No. 4,667,005 discloses crystalline alphamonoolefin copolymers of C.sub.2-8 alphamonoolefins and an olefinic benzocyclobutene monomer.
U.S. Pat. No. 4,680,353 teaches a process for the preparation of polymers of vinyl aromatic monomers having a stereoregular structure of high syndiotacticity by the use of coordination catalysts, particularly catalysts comprising a certain transition metal compound and a polyalkylaluminoxane. Other coordination catalysts for the preparation of syndiotactic polystyrene are disclosed in U.S. Pat. Nos. 4,680,353, 4,774,301 and 4,808,680: EP's 271,874 and 271,875: and copending U.S. patent application Ser. No. 64,282, filed June 17, 1987. For the teachings contained therein, the above references are incorporated in their entirety by reference thereto.
The present invention is directed to a new class of polymers having a stereoregular structure of high syndiotacticity which are capable of crosslinking thereby imparting new and improved properties to such polymers.